[9 days teach you south Cass 9.1] 11-side grid earthwork computing

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In this lesson, we will learn about square grid earthwork computing.

Course Teaching Plan

Earthwork calculation plays an important role in earthwork and is an important part of engineering design. The earthwork volume is an important basis for Vertical planning or adjustment, and is directly related to the project cost. Therefore, when calculating earthwork, we must be realistic, keep improving, and be realistic. Earthwork calculation is a key link in the internal processing of earthwork measurement. Common methods include DTM method, cross section method, square grid method, and contour method. They have their own characteristics and have different advantages and limitations, select different calculation methods as needed. The South cass9.1 is also a commonly used computing software. It is easy to operate, versatile, efficient, fast, and accurate.

In this lesson, we will learnCass9.1In the software, the square grid method is used to calculate the earthwork volume.

1-square grid method Computing Features

The square grid method is simple, intuitive, easy to master, versatile, and widely used. However, the disadvantages of the square grid method are that the calculation accuracy of the Earth volume of complex terrain is relatively low, which is inferior to that of the DTM method. The square grid method is favored by many owners because it can be directly reviewed by a pen or calculator.

The design surface calculated by the square grid method in the southern cass9.1 software can be a plane or. one Direction slope: slope [datum point], B. two slopes in different directions: slope [baseline]), but also multiple slopes (completed using a tin file ). In this way, it can meet the earthwork calculation in different situations and solve many problems in earthwork calculation.

Calculation principle of the square grid method

A. Calculation of construction elevation

Construction elevation = original ground elevation-design elevation (H = H original-h)

Note: The Construction elevation (height) can be positive or negative, positive is the excavation height, negative is the filling height, (figure-5 ).

B. Calculate the zero point

When a square grid contains both filling or digging, you must first calculate the zero point on the side of the square grid and mark it on the square grid to connect the zero line at zero point, it is the dividing line between the filling Area and the excavation area (excavation line ).

The zero point is calculated based on the construction elevation and the side length of the square grid, as shown in figure (figure-1 ):

;

Formula medium, -- the distance from the Angle Point to the zero point (m );

, -- The construction elevation (M) of adjacent two points, with absolute values;

A-- The side length of the square grid (m ).

Figure-1 Zero Point Calculation

C. Earthwork Calculation Formula

Table 1 calculation formula of the square grid method

A little fill or excavation (triangle)

2-point fill or excavation (ladder)

Three-point filling or excavation (pentagram)

Four-point filling or excavation (square)

Note:

1) A -- side length of the square grid (m );

B. C: The length (m) from zero to one corner );

H1, H2, H3, H4 -- the construction elevation (m) of the four-point of the square grid, which is substituted with the absolute value;

Σ H-sum of the fill or excavation construction elevation (m), which is substituted with the absolute value;

-- Excavation or fill volume (m ).

2) Table 1 formula is obtained by multiplying the bottom area of each calculated graph by the average construction elevation.

With the development of surveying and mapping and the advancement of computer technology, the southern cass9.1 software has developed specialized earthwork computing functions based on the theory of manual earthwork calculation and has been further improved. Earthwork computing gradually replaces manual computing by software computing, and is further applied in the software using the most basic principle or formula (such as table 1) of manual computing. The formula for calculating the zero point position in the square grid method and the formula for digging (filling) Parties in different situations are well applied in the southern cass9.1 software.

3-way grid method calculation steps

The square grid is used to calculate the earthwork quantity in each square by generating a square grid based on the ground coordinate (x, y, z) and design elevation measured in the field, finally, the earthwork quantity of the filling party and the digging party within the specified range is accumulated, and the demarcation line of the filling party is drawn.

The system first adds the elevation on the four corners of the Square (if there is no elevation point on the corner, the elevation is obtained through interpolation of the surrounding height points), and the average value is reduced from the design elevation. Then, the area of each square is obtained through the specified square edge length, and the quantity of square [4] is obtained by using the cube volume calculation formula.

The square grid method is used to calculate the earth volume. The design surface can be a plane, a slope, or a triangular network, such

1. Operation steps when the design plane is a plane:

(1) Use a composite line to draw the area of the earth to be calculated. It must be closed, but try not to fit it. This is because the curve that has been fitted will be iterated by line during earthwork calculation, which affects the accuracy of the calculation result.

(2) Select the "Project Application Grid Method earthwork calculation" command.

(3) The command line prompts "select calculation region boundary line"; select the boundary line of the earthwork calculation region (close the compound line ).

(4) On the screen, the calculation dialog box is displayed. In the dialog box, select the desired coordinate file. In the "design area" bar, select "plane" and enter the Target elevation; in the "square width" column, enter the square grid width, which is the side length of each square. The default value is 20 meters.

(5) Click "OK" and the command line prompts:

Min elevation = XX. xxx, Max elevation = XX. xxx

Total fill = XXXX. x cubic meters, total excavation = xxx. x cubic meters

At the same time, the square grid analyzed in the figure is drawn to fill in the cut-off line (Green Line) of the excavation, and each square is filled with the excavation, each line of the excavation and each column of the fill. Result.

 

2. Operation steps when the design surface is inclined:

When the design plane is inclined, the operation steps are basically the same as the plane. The difference is that in the "design Plane" column of the square grid earthwork calculation dialog box, select "slope [datum point]" or "slope [baseline ]".

--> If the designed surface is a slope (datum point), you need to determine the coordinates of the slope, the datum point and the downward point, and the design elevation of the datum point.

(1) Click "pick" and the command line prompts:

(2) design surface datum point: determine the design surface datum point;

(3) Specify the downward direction of the Slope Design: The downward direction of the Point slope design;

Map of earthwork calculation results by square grid method (menu command)

--> If the designed surface is a slope (baseline), you need to enter the slope and take two points on the baseline line and a point in the downward direction of the baseline, finally, enter the design elevation of the two points on the benchmark line for calculation.

(4) Click "pick" and the command line prompts:

(5) point to get the first point of the baseline: point to get the baseline;

(6) second point of the baseline for a vertex: another point of the baseline for a vertex;

(7) specify a point in which the design elevation falls below the baseline direction: Specify the low side of both sides of the baseline direction;

3. Operation steps when the design area is a tin file:

When the design surface is a tin file, the earthwork can be calculated during the two periods, or the design surface can be calculated as the earthwork of multiple slopes.

Calculate the earthwork in the two periods, and measure the elevation data of the first and second phases of the ground points in the field respectively. The region boundary of the earthwork in the second period must be consistent. Generally, the region boundary cannot be completely the same during field measurement, but it can be adjusted to the same during internal processing, and the elevation data of each boundary can be obtained using the inner interpolation method.

The second phase of the ground point elevation data to generate a tin file, the specific operation using South caass9.1 software in the "Drawing Processing" and "Contour" Two menu functions in accordance with the corresponding prompts to complete.

◆ In the "Drawing Processing" menu: Set the display area → change the current drawing scale → extend the range → connect the border line.

◆ In the "Contour" menu: Create a DTM (or a complete DTM drawing) → select a line → create a tin mesh → modify a result to save a disk → access a tin mesh → write a file.

◆ When you click "Write File", a "input tin file name" dialog box appears, prompting you to save the formed tin in the format of *. sjw extension to the specified file.

During the second period, the tin file used for earthwork calculation is completed step by step. With this tin file, it can be used for Earthwork Calculation during the second period.

During the second period, when the design surface of earthwork calculation is a "Triangle file", the operation steps are basically the same as those of the "plane, the difference is that when you select the "coordinate data file" in the square grid earthwork calculation dialog box, you must select the first phase of the ground point elevation data, and in the "design area" column, select "Triangle network file ". When selecting a tin file, you must select a tin that consists of the second phase of the ground point elevation data.

--> If the calculation design surface is the earthwork of multiple slopes:

When the design surface is multiple slopes, This method is suitable for calculation of earthwork in a planning area. different slopes have different vertical elevation levels. The calculation method is basically the same as the calculation of earthwork during the two periods by using the "Tin File". The difference is that the vertical elevation is converted into a high point that can be identified by the Southern cass9.1 software, then use these process points to generate a tin file in the same way.

In southern cass9.1, the earthwork calculation module of the square grid method is used and verified in a number of projects, all of which have good results. Although the accuracy calculated by the square grid method is less than that calculated by the DTM method, as long as the external and internal fields are properly processed, a high-precision and practical earthwork result will also be obtained.

 

[9 days teach you south Cass 9.1] 11-side grid earthwork computing